Effects of Greenhouse Gases - Term Paper Example

? Effects of Greenhouse Gases (GHGs) and Ways to Reduce GHG Emission: A Review Greenhouse gas (GHG) emission has been one of the most devastating problems facing the world today. Greenhouse gases have been recorded to have continuously increased since the dawn of the industrial revolution. Major GHGs in the atmosphere are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), water vapor, ozone (O3) and chlorofluorocarbons (CFCs). The purpose of this paper is to review the debilitating effects of increased concentration of GHGs in the atmosphere and the ramifications of this problem to the different constituents of the ecosystem. This paper also seeks to suggest plausible ways on how to reduce GHG emission in order to diminish the impacts of global warming. Data from various sources revealed that the primordial effect of increased GHG is global warming, which is also implicated in changes in the pattern of precipitation and rainfall, sea water level, melting of glaciers, and animal and plant species composition and distribution. Several strategies to reduce GHG emissions are reforestation, proper waste disposal management, and the use of renewable energy such as water, solar energy and thermal energy to generate electricity instead of using fossil fuels. Introduction Greenhouse gases (GHGs), consisting primarily of water vapor, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), ozone, and chlorofluorocarbons (CFCs) are those gases that can absorb infrared radiation from the atmosphere. These gases are capable of trapping heat, resulting to warming of the earth’s surface (Snyder et al., 2009; Reay and Hogan,2010). Greenhouse gas emission and the human activities associated with increasing GHG concentration in the atmosphere, is perhaps one of the most controversial issues worldwide yet to be resolved. In fact, it has been reported that since the industrial period, the concentration of these GHGs in the atmosphere has been constantly escalating (Krupa and Kickert, 1989; IPCC, 2011). A time-lapse carbon dioxide monitoring conducted by Muller et al. (2007) revealed that the present CO2 concentration in the troposphere is, by far, the highest level ever recorded during the last 670,000 years, making CO2 the most anthropogenically-driven GHG. Meanwhile, the total amount of atmospheric methane was revealed to have increased by as much as 15% at the end of the 18th century and almost tripled over the last 150 years. Although methane concentration is much less compared to that of CO2, Ramaswamy et al. (2001) reported that CH4 is actually 23 times more potent as a greenhouse gas in comparison to CO2. Ramaswamy and colleagues (2001) also provided evidence that nitrous oxide is even more effective per molecule as a GHG than CH4 and 296 times more potent than CO2. The presence of GHGs in the atmosphere accounts for the phenomenon known as greenhouse effect, so called because the mechanism by which it works is reminiscent to that of a greenhouse. Shown in Figure 1 is a diagram illustrating the processes governing the greenhouse effect. As sunlight strikes the planet, radiant energy from the sun with short wavelengths is absorbed by the earth’s surface without being caught trapped in the atmosphere (Krupa and Kickert, 1989). As this energy is absorbed, it warms the earth’s surfaces and is then re-radiated back into the atmosphere at longer wavelengths. Once again, this long-wavelength energy is captured by GHGs in the atmosphere and is reflected in different directions. Energy directed upwards is released into space while energy directed downwards, which accounts for 90% of the long-wavelength emission, goes back to the earth (Pidwirny, 2006). It must be noted, however, that the greenhouse effect is a naturally-occurring phenomenon. In fact, it makes the earth habitable (Krupa and Kickert, 1989).On the other hand, if GHGs in the atmosphere increase beyond the normal range of GHG levels, the greenhouse effect is enhanced, posing a great threat to all of earth’s inhabitants. Figure 1. Processes governing the greenhouse effect. Courtesy of: Okanagan University College, Canada, Department of Geography, University of Oxford, School of Geography, United States Environmental Protection Agency (EPA), Washington; Climate Change 1995, The Science of Climate Change, Contribution of Working Group I to the Second Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), UNEP and WMO (World Meteorological Organization, Cambridge University Press, 1996. The alarming increase in GHGs over the last century has culminated in the formation of environmental agencies and organizations such as the Intergovernmental Panel on Climate Change (IPCC) and United Nations' Framework Convention on Climate Change (UNFCCC). These organizations aim to monitor GHG levels, bring down and stabilize its level to a point where dangerous climate interference is prevented (Gustavsson, 2000). Since the birth of these environmental organizations, many new policies, regulations, and agreement among different countries have been released and implemented to reduce GHG emissions (Guo, and Zhou, 2007; Pearce and Harris, 2007; Hwang, 2011). But what exactly are the dangers of the greenhouse gas effect? This paper reviews the harmful consequences of the enhanced greenhouse effect and how this occurrence has affected the way humans lived over the years. In addition, this paper seeks to enumerate the possible ways to reduce and stabilize GHG emission at a level that will no longer put the earth’s biotic components in danger. Impacts of greenhouse gases: the greenhouse effect and its ramifications The primordial and most concerning outcome of enhanced greenhouse effect is global warming, technically defined as the warming of the lower atmosphere( Krupa and Kickert, 1989). However, the problem caused by the greenhouse effect doesn’t end with global warming. In fact, global warming is a phenomenon that casts a plethora of impacts in the stability of every component of the ecosystem, directly or indirectly. Wuebles et al. (1989, as cited by Krupa and Kickert, 1989) showed evidence that global surface temperature has increased by an average of 3.0 oC between the 19th to the 21st century. As the earth’s atmosphere increases, the saturation vapor pressure also increases, resulting to a proportional increase in air humidity. The high concentration of water vapor (since water vapor is a GHG) further intensifies the warming (IPCC, 2007). Also, because the atmosphere is hotter than it used to be, snow caps and glaciers have melted and increased sea water level. In fact, according to UNEP/GRID-Arendal (2000), sea water level at a global scale has surged to about 10-25 cm over the last 100 years. Shown in Figure 2 is the amount of sea water level (cm) change over the years. If sea level continues to rise, low-lying cities will be underwater, wetlands, which are inhabited by many fauna and flora will be inundated, and salinity of river deltas will change, resulting to alteration in marine species and plant composition (EPA, 2011). Animals and plants that cannot thrive in more saline water will have to migrate to a more suitable environment. It might even be possible for these animals and plants to be extinct. Salinity alteration is not the only problem that affects marine life. The warming of the oceans is also a strong driving force that brings about a significant change in the living components underwater. In a review conducted by Crabbe and James (2008) on the effects of high temperatures on coral reefs, it was indicated that the frequency of coral bleaching will rise rapidly, especially in the Carribean, Southeast Asia, and the Great Barrier Reef. Note that coral reefs provide the breeding ground for approximately one-third of fish species and hundreds of other marine creatures. The decline in fish supply associated with the destruction of coral reefs will significantly weaken the fish industry, especially the small-time fisher folks (Crabbe and James, 2008). Figure 2. Sea water level over the years. Douglas, B , 1997. "Global Sea Rise: A Redetermination". Surveys in Geophysics 18: 279 Another significant changes brought about by global warming is increase in the intensity of rainfall. In an extensive literature review conducted by Goudie (2006), it was reported that precipitation rate has increased in a number of countries such as Canada, Australia, Japan, South America, and Europe during the warmer decades. This increase in rainfall is greatly implicated in the occurrence of flood, landslides, and soil erosion (Goudie, 2006). Perhaps, one of the most troubling impacts of global warming to weather disturbances is the probable change in distribution, frequency, and intensity of tropical cyclones (Goudie, 2006). Knutson et al. (1998) simulated the activity and process of hurricane formation when sea water temperature was increased by 2.2 oC and found that hurricanes became more intense approximate by 7 m/s wind speed. This finding was also supported by Emanuel (2005), reporting that over the past 30 years, tropical cyclones have become more destructive, exhibiting approximately 15% and 60% increase in wind intensity and storm life span. It is logical to think that the more destructive these hurricanes become, the more costly and tremendous their damage will be. Because of the changes in the pattern of precipitation and length of seasons, plants have been observed to change the timing of their activities (Primack et al., 2009). Several studies have reported that some plants flower or bear fruit earlier than they usually do (Ahas, 1999; Defila and Clot, 2001). Some shed their leaves earlier than expected. According to Primack et al. (2009), if plant activities continue to change at different rates, interaction among different plant species and between animals and plants will be disturbed. This may eventually lead to species extinction. Ways to reduce greenhouse gases The best way to resolve the issue of global warming and its implications is to reduce the emission of greenhouse gases. In this regard, various strategies that aim to cut back anthropogenic GHG emission have been implemented as a way to mitigate enhanced greenhouse effect (Pearce and Harris, 2007; Lombardi et al., 2008). According to IPCC (2007), the use of fossil fuels has been among the greatest contributors to the increase in atmospheric carbon dioxide over the past century. Coal, for instance, accounts for approximately half of the electricity generated in the United States (Energy Information Administration, 2011). Hence, the use of other resources such as water, wind, solar energy, and thermal energy to produce electricity must be maximized. Instead of using vehicles powered by gasoline and petroleum, electric and plug-in hybrid vehicles must be encouraged (Amjad et al., 2011). Even the simple act of not burning plastics and rubber can help in reducing GHG emission. On the other hand, landfills have long been recognized as a significant contributor to greenhouse gas emission. By virtue of solid waste decomposition, landfills account for one of the major sources of methane (Ritzkowski, and Stegmann, 2007). Some countries have implemented landfill gas capture, aerobic landfilling, landfill capping and pre-composting of waster prior to landfilling to mitigate GHG emission by landfills (Lou and Nair, 2009). 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